Function.prototype.myCall = function (content = global, ...args) {
  if (content === undefined || content === null || content === "")
    content = global;
  if (typeof content !== "object") content = new Object(content);
  const key = Symbol();
  content[key] = this;
  const res = content[key](...args);
  delete content[key];
  return res;
};
const a = {
  a: 123123,
  b: 324234,
};
const obj = {
  a: 300,
  b: 200,
  c: 100,
  fun3(a, b, c) {
    this.a = a;
    this.b = b;
    this.c = c;
    console.log(this.a, this.b, this.c, obj.a, obj.b);
  },
};
obj.fun3.myCall(a, 1, 2, 3);
console.log(obj);
console.log(a);
